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DRV10987: bldc motor tuning

Rocky Selva
Prodigy 185 points
Part Number: DRV10987
Other Parts Discussed in Thread: DRV10983

I was using DRV10983 before and now using DRV10987,while tuning found 4 new parameters which actually affecting startup and peak power performance.

Since i dont have not much knowledge about following parameters and want to know how to tune it ,so can you please explain t for bldc motor?

I have already gone though tuning guide and datasheet but not able to understand it, so need your help in this.

New Parameters are:

DEVICE OPTION:

1> SLEW RATE

2> DUTY CYCLE LIMIT

3> SPEED SPECTRUM MODULATION

4> TEMP WARNING ACTION

  • 0
    TI__Intellectual 1555 points

    Hi Rocky,

    1. Slew rate, if you are having EMI issue you want to slow down this setting. I would recommend the fastest one best efficiency.

    2. Duty cycle limit - This really depends on your applicatio need. If you dont have certain requirement on Speed pin to duty cycle, I would recommend 01 setting.

    3 This is another tool to improve EMI, if you don't have an issue with EMI, we recommend no sperad spectrum

    4. temp warning action - If you were using DRV10983 and wants the same behavior, I woudld recommend "No current limit"

    I hope this helps.

    Thanks,

    Seil

  • 0 in reply to Seil Oh
    Prodigy 185 points

    Hi seil ,

    Thanks for your reply. As per your suggestion i kept following setting:

    slew rate = 120v/us.

    Duty cycle limit = 10% (0% below 1.5%) // i am using I2C based speed control option

    Spread spectrum modulation = NO  spread spectrum modulation.

    Temp warning option = NO current limit on warning.

    I will experiment with this more and let you know the results.

    One more doubt i have is, sometimes i observed  continous Noise(every 1/2 sec delay repeatative noise  which is IPD noise) and no error shown in gui but it gets hang and its like if i change some setting of parameter on gui it is not allowing me to do that.

    This issue is with IPD enable case only.

    This issue is solved by keeping ipd current threshold less than 2A.

    But increases chances of ipd fail.

    Is there any thing else i can tune to increase threshold.

  • 0 in reply to Rocky Selva
    Prodigy 185 points
    on point added in above note is that just now checked error in case of noise that is current limit lock 0.
  • 0 in reply to Rocky Selva
    TI__Intellectual 1555 points
    Rocky,

    Can you drive V1P8 pin externally with 2.2V and see problem goes away? I want to see whether high current switching event create voltage different which on different ground which can cause V1P8V UVLO issue.

    Thanks,
    Seil
  • 0 in reply to Seil Oh
    Prodigy 185 points
    Hi Rocky,

    Let me clear from my side because your solution is little bit not clear for me.
    My issue is
    first point is
    IPD works suceessfully with 3.3A tristate with DRV10983, but with 10987 its ipd fails shows overcurrent error and continuous "tung-tung" like sound is there which i never observed with DRV10983.
    second point is
    this issue get resolved if i keep current threshold less than 2A. Also with Break state it works successfully with 3.3A.
    why it is so?
  • 0 in reply to Rocky Selva
    Prodigy 185 points
    hi seil this is rocky ,waiting for your replay.
  • 0 in reply to Rocky Selva
    TI__Intellectual 1555 points
    Rocky,

    my thought is that pumping higher current into motor driver i creating ground bounce and it results in UVLO for 1p8V.

    Thanks
    Seil